Common table salt is a white crystalline solid having a salty taste, which is composed primarily of sodium chloride (NaCl). Salt is widely used as a seasoning, imparting taste to food in both Western and Eastern countries, and is also a nutrient that is essential for sustaining the body's metabolism. It helps regulate osmotic pressure and maintain acid-base balance, and is involved in the transmission of nerve impulses. Salt is also a constituent of digestive juices and is needed in many enzymatic reactions. Many recent studies, however, have revealed that excess sodium intake may contribute to hypertension, diabetes, gastric cancer, and other adult diseases.
There are various types of salt for human consumption: natural sea salt, rock salt, refined salt, artificially regenerated salt, modified salt, and processed salt. Natural sea salt is obtained from seawater, which is captured in shallow ponds and is evaporated using the natural processes of sun and wind to fully concentrate the brine. Rock salt is obtained from underground deposits of the mineral halite using a mining technique by which the rock is crushed and broken into smaller pieces, which are then screened and processed to yield rock salt having over 96% salt content. Refined salt, having a purity of over 99% sodium chloride, is created by passing seawater through an ion exchange membrane to ionize only the salt into sodium and chloride ions, evaporating moisture from the saturated brine in an evaporator, centrifuging the brine to reduce moisture, and fully drying the brine to a moisture content of 0.01% using a drier. The artificially regenerated salt is prepared by subjecting raw salt to a process including dissolution, dewatering, dryness and finally recrystallization. Modified salt is obtained by modifying raw salt through roasting, burning, melting, or the like. Processed salt contains food additives. However, the conventional salt forms are composed of mainly sodium chloride (90-99%), but rarely contain minerals that are beneficial to the health of humans.
Some functional salts having low sodium contents and supplemented with mineral nutrients including potassium are currently available on the market. For example, a low-sodium salt product, prepared from rock salt, has a sodium chloride content of about 57%, and is artificially supplemented with minerals.
Some efforts have been made to provide substitutes for table salt having high sodium content. For example, Korean Pat. Laid-Open Publication Nos. 10-2001-83036, 10-2001-83037 and 10-2002-38282 disclose a method of preparing a salt substitute from a halophyte, such as Suaeda japonica, Suaeda maritima, Aster tripolium, or Salicornia europaea. The method includes collecting Salicornia europaea, washing the plant with seawater or salty water to remove impurities, such as the mud of mud-flat sediment, from the plant, cutting or chopping the plant, heating the plant for over 3 hours, compressing the resulting extract, and recovering the filtrate to yield a liquid salt. To provide a crystalline salt, the pressing can be dried, placed in a ceramic container, and subjected to a three-step ashing process, which is performed at 150-250° C. for over 30 minutes, then at 500° C. for over 2 hours and finally at 700° C. for over 2 hours. In some cases, the plant is subjected directly to the ashing process without heat extraction so as to obtain a salt.
However, the salt obtained through the ashing process described in the above patent applications does not contain amino acids. Of amino acids, L-lysine in particular masks the bitter taste of sodium. For this reason, some conventional mineral salts are additionally supplemented with L-lysine.
The liquid salt described in the patent applications, which is obtained through hot water extraction and compression not undergoing an ashing process, has a sodium chloride content that is not high, and its mineral content can not be controlled.